1. Field of the Invention
This application relates to cables. More particularly, this application relates to composite fiber optic, power and signal type cables.
2. Related Art
In the art of cable production, composite cables are cables that combine both power conductors as well as signal cables within a single outer jacket. Such cables can be used for many self contained power/signal transmission connections. A common use for such composite cables is for connecting cameras, such as CCD security cameras, for providing power, signal transmission and actuator control of the camera. See for example prior art FIG. 1 wherein various cable types are included within a single jacket.
A number of such composite cables are offered with various constructions, typically as an assembly of copper and fiber elements. However, such prior art cables lack the ability to deliver the power necessary over distances of 300 to 5000 ft, nor the ability to carry a 20-400 volt range and 0.5 to 5 amps with sufficient ground safety factors protecting from eventual flex failure. Furthermore, the prior art cables also lack sufficient jacket crosslink to survive 24 hours at 100 degree C. in heavy diesel fuel. An exemplary standard that employs such test parameters is EIA/TIA-455-12A.
To achieve such a cable it is highly desirable to have a well-crosslinked polymer jacket for the composite cable. Crosslinking of the polymer in the jacket provides, among other advantages, improved heat resistance, decreased permeability and better abrasion resistance.
One manner in achieving fast and complete crosslinking of the polymer jacket, so as to make it sufficiently crosslinked to survive diesel oil soak, is to use a process of electron beam processing (or E-beam processing) where the jacket is subjected to irradiation by a high energy electron beam. Although this has the advantage of providing a well cross linked jacket, if optical fibers are included in the cable under this jacket process, the fiber element of the composite cable is also inadvertently subject to the irradiation as well. Such irradiation from an E-beam processor, as with any radiation exposure (background radiation post installation etc. . . . ) can cause noticeable signal attenuation in the fibers, as the material of the fibers is altered/damaged during the irradiation process.